Question on Merc 305

[Bry21317]

I have a question. I had a Mechanic do an upgrade to my boat. The engine is a Mercruiser 305, non Vortec heads. It is a 94 model, we added an Edelbrock RPM Air Gap Intake and an Edelbrock 1409 Marine Carb.

The Mechanic that put it on said it was flooding as the Stock fuel pump was putting out to myc fuel pressure. Same fuel pump that ran perfect with the Original 2bbl Rocester carb. He put a regulator on the fuel line and said it was better in the shop. I think he has the Fuel Pressure set to around 2.5, but we have not yet taken it to the water to run it yet. Can you tell me what it should be set at?

I will be taking it out this weekend with him, to see how everything is working. I just want to be on the safe side knowing where the fuel pressure should be set for this setup.

Thanks,
Bryan

 

[John_S]

Re: Question on Merc 305

Per Merc Service Manual #17:
Mechanical Fuel
Pump Pressure
(at 1800 RPM)
3-7 PSI (21-48 kPa)

 

[mkast]

Re: Question on Merc 305

The Mercruiser manual states "five an one quarter to six an one half psi, from idle to 1000rpm."

 

[Bry21317]

Re: Question on Merc 305

Thanks. Thats why I was wondering if him having it set at 3.5 was to low, and I think it is. I will have to find this out, when we run it and watch the plugs.

Bryan

 

[bomar76]

Re: Question on Merc 305

Way too low.
Check float setting (and floats) in carb.

 

[wca_tim]

Re: Question on Merc 305

My Edelbrock 1409 fuel pressure regulatror is set at 5.5 per the owner's manual... Edelbrock says no more than 6.0 and that it should not drop below 2.0 at any rpm for max performance.

It has been one of the easiest carbs I've ever set up. If I hadn't needed to rejet to get the fuel mix right for my set-up, I would not have had to touch it yet.

Hope this is helpful.

 

[Coors]

Re: Question on Merc 305

That regulator marine?
And not needed- the float/needle and seat have a problem.

 

[Don S]

Re: Question on Merc 305

You have carb problems, not fuel pump pressure problems.
I also think you are another poster that should also be looking for another mechanic.

 

[Coors]

Re: Question on Merc 305

You have carb problems, not fuel pump pressure problems.
I also think you are another poster that should also be looking for another mechanic.

Do the bad mechanics show up in the spring, like cracked blocks?

 

[Bondo]

Re: Question on Merc 305

The Mechanic that put it on said it was flooding as the Stock fuel pump was putting out to myc fuel pressure. Same fuel pump that ran perfect with the Original 2bbl Rocester carb.

Ayuh,..... I guess I'm atad late with this,....
But,......

You need a New Mechanic,...... Not a fuel pressure regulator......